/********************************************************************************************
* Abstract: run tests against known answer test vectors
*
* Modified from a file created by Bassham, Lawrence E (Fed) on 8/29/17.
* Copyright © 2017 Bassham, Lawrence E (Fed). All rights reserved.
*********************************************************************************************/

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <rng.h>
#include "api.h"


#define	MAX_MARKER_LEN		50
#define KAT_SUCCESS          0
#define KAT_FILE_OPEN_ERROR -1
#define KAT_VERIFICATION_ERROR -2
#define KAT_DATA_ERROR      -3
#define KAT_CRYPTO_FAILURE  -4

int		FindMarker(FILE *infile, const char *marker);
int		ReadHex(FILE *infile, unsigned char *A, int Length, char *str);
void	fprintBstr(FILE *fp, char *S, unsigned char *A, unsigned long long L);

int
main()
{
	char                fn_rsp[64];
	FILE                *fp_rsp;
	unsigned char       seed[48];
	unsigned char       ct[CRYPTO_CIPHERTEXTBYTES], ss[CRYPTO_BYTES], ss1[CRYPTO_BYTES], ct_rsp[CRYPTO_CIPHERTEXTBYTES], ss_rsp[CRYPTO_BYTES];
	int                 count;
	int                 done;
	unsigned char       pk[CRYPTO_PUBLICKEYBYTES], sk[CRYPTO_SECRETKEYBYTES], pk_rsp[CRYPTO_PUBLICKEYBYTES], sk_rsp[CRYPTO_SECRETKEYBYTES];
	int                 ret_val;

	sprintf(fn_rsp, "../../../KAT/PQCkemKAT_%d.rsp", CRYPTO_SECRETKEYBYTES);
	if ( (fp_rsp = fopen(fn_rsp, "r")) == NULL ) {
		printf("Couldn't open <%s> for read\n", fn_rsp);
		return KAT_FILE_OPEN_ERROR;
	}

	printf("# %s\n\n", CRYPTO_ALGNAME);
	done = 0;
	do {
		if ( FindMarker(fp_rsp, "count = ") ) {
			if (fscanf(fp_rsp, "%d", &count) != 1) {
				done = 1;
				break;
			}
		} else {
			done = 1;
			break;
		}

		if ( !ReadHex(fp_rsp, seed, 48, "seed = ") ) {
			printf("ERROR: unable to read 'seed' from <%s>\n", fn_rsp);
			return KAT_DATA_ERROR;
		}

		randombytes_init(seed, NULL, 256);

		// Generate the public/private keypair
		if ( (ret_val = crypto_kem_keypair(pk, sk)) != 0) {
			printf("crypto_kem_keypair returned <%d>\n", ret_val);
			return KAT_CRYPTO_FAILURE;
		}
		if ( !ReadHex(fp_rsp, pk_rsp, CRYPTO_PUBLICKEYBYTES, "pk = ") ) {
			printf("ERROR: unable to read 'pk' from <%s>\n", fn_rsp);
			return KAT_DATA_ERROR;
		}
		if ( !ReadHex(fp_rsp, sk_rsp, CRYPTO_SECRETKEYBYTES, "sk = ") ) {
			printf("ERROR: unable to read 'sk' from <%s>\n", fn_rsp);
			return KAT_DATA_ERROR;
		}

		if(memcmp(pk,pk_rsp,CRYPTO_PUBLICKEYBYTES)!=0){
			printf("ERROR: pk is different from <%s>\n", fn_rsp);
			return KAT_VERIFICATION_ERROR;
		}
		if(memcmp(sk,sk_rsp,CRYPTO_SECRETKEYBYTES)!=0){
			printf("ERROR: sk is different from <%s>\n", fn_rsp);
			return KAT_VERIFICATION_ERROR;
		}

		if ( (ret_val = crypto_kem_enc(ct, ss, pk)) != 0) {
			printf("crypto_kem_enc returned <%d>\n", ret_val);
			return KAT_CRYPTO_FAILURE;
		}

		if ( !ReadHex(fp_rsp, ct_rsp, CRYPTO_CIPHERTEXTBYTES, "ct = ") ) {
			printf("ERROR: unable to read 'pk' from <%s>\n", fn_rsp);
			return KAT_DATA_ERROR;
		}
		if ( !ReadHex(fp_rsp, ss_rsp, CRYPTO_BYTES, "ss = ") ) {
			printf("ERROR: unable to read 'sk' from <%s>\n", fn_rsp);
			return KAT_DATA_ERROR;
		}

		if(memcmp(ct,ct_rsp,CRYPTO_CIPHERTEXTBYTES)!=0){
			printf("ERROR: ct is different from <%s>\n", fn_rsp);
			return KAT_VERIFICATION_ERROR;
		}
		if(memcmp(ss,ss_rsp,CRYPTO_BYTES)!=0){
			printf("ERROR: ss is different from <%s>\n", fn_rsp);
			return KAT_VERIFICATION_ERROR;
		}

		if ( (ret_val = crypto_kem_dec(ss1, ct, sk)) != 0) {
			printf("crypto_kem_dec returned <%d>\n", ret_val);
			return KAT_CRYPTO_FAILURE;
		}

		if ( memcmp(ss, ss1, CRYPTO_BYTES) ) {
			printf("crypto_kem_dec returned bad 'ss' value\n");
			return KAT_CRYPTO_FAILURE;
		}

	} while ( !done );

	fclose(fp_rsp);
	printf("Known Answer Tests PASSED. \n");
	printf("\n\n");

	return KAT_SUCCESS;
}


//
// ALLOW TO READ HEXADECIMAL ENTRY (KEYS, DATA, TEXT, etc.)
//

int
FindMarker(FILE *infile, const char *marker)
{
	char	line[MAX_MARKER_LEN];
	int		i, len;
	int curr_line;

	len = (int)strlen(marker);
	if ( len > MAX_MARKER_LEN-1 )
		len = MAX_MARKER_LEN-1;

	for ( i=0; i<len; i++ )
	{
		curr_line = fgetc(infile);
		line[i] = curr_line;
		if (curr_line == EOF )
			return 0;
	}
	line[len] = '\0';

	while ( 1 ) {
		if ( !strncmp(line, marker, len) )
			return 1;

		for ( i=0; i<len-1; i++ )
			line[i] = line[i+1];
		curr_line = fgetc(infile);
		line[len-1] = curr_line;
		if (curr_line == EOF )
			return 0;
		line[len] = '\0';
	}

	// shouldn't get here
	return 0;
}

//
// ALLOW TO READ HEXADECIMAL ENTRY (KEYS, DATA, TEXT, etc.)
//
int
ReadHex(FILE *infile, unsigned char *A, int Length, char *str)
{
	int			i, ch, started;
	unsigned char	ich;

	if ( Length == 0 ) {
		A[0] = 0x00;
		return 1;
	}
	memset(A, 0x00, Length);
	started = 0;
	if ( FindMarker(infile, str) )
		while ( (ch = fgetc(infile)) != EOF ) {
			if ( !isxdigit(ch) ) {
				if ( !started ) {
					if ( ch == '\n' )
						break;
					else
						continue;
				}
				else
					break;
			}
			started = 1;
			if ( (ch >= '0') && (ch <= '9') )
				ich = ch - '0';
			else if ( (ch >= 'A') && (ch <= 'F') )
				ich = ch - 'A' + 10;
			else if ( (ch >= 'a') && (ch <= 'f') )
				ich = ch - 'a' + 10;
			else // shouldn't ever get here
				ich = 0;

			for ( i=0; i<Length-1; i++ )
				A[i] = (A[i] << 4) | (A[i+1] >> 4);
			A[Length-1] = (A[Length-1] << 4) | ich;
		}
	else
		return 0;

	return 1;
}

void
fprintBstr(FILE *fp, char *S, unsigned char *A, unsigned long long L)
{
	unsigned long long  i;

	fprintf(fp, "%s", S);

	for ( i=0; i<L; i++ )
		fprintf(fp, "%02X", A[i]);

	if ( L == 0 )
		fprintf(fp, "00");

	fprintf(fp, "\n");
}
